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1. Does anyone know what this equipment is for?

Hello, I have found this chemistry equipment, but I cannot determine what it is for. I have a suspicion it is for measuring boiling point temperature elevation. I have included a drawing of how I think it should go together. It consists of a conical flask connected to a graduated boiling tube...
2. Equation from neuroscience textbook, regarding modeling neurons

Hello, I am trying to understand an equation from the textbook "Theory of neural information processing systems" by Coolen, Sullich and Kuhn. The book states that "the evolution in time of the postsynpatic potential V(t) can be written as a linear differential equation of the form: \frac...
3. Applied maths, monotonic function

Hello, The equation is from a chemistry calculation; the textbook claims that the function is monotonic, without specifying whether it is monotonically increasing or decreasing. Depending on the starting conditions, the function can look different; I basically want to know if the following is...
4. PH meter design

Hello! I have a question concerning the functioning of a pH meter. All the sources online that I can find either omit, I think, important information, or describe it in "technical terms" with equations. I would like to know what is happening at the level of the distribution and movement of...
5. Velocity is proportional to distance

Homework Statement An object starts from rest at the origin and moves in the positive x direction. The velocity is proportional to the displacment. I am trying to find the equation linking velocity to displacement. Homework Equations Since the object starts at rest and then moves in the...
6. Average speed question: forwards then backwards

Homework Statement An object starts at the origin, position A; then travels 20 m to position B; then returns to position A. From A to B the average speed is 10 m/s; on its way back the average speed is 6 m/s. What is the average speed for the entire trip? Homework Equations average speed =...
7. Steampunk-esque novels

Hello! I have started to take an interest in steampunk and related genres. I read China Mieville's Perdido Street Station and enjoyed his writing style and some of the ideas and imaginative characters. However, it wasn't "pure" steampunk. I tried The difference Engine but it didn't provide...
8. Pycnometer equation

hello! On wiki, regarding specific gravity, it gives the derivation for the pycnometer equation for determining specific gravity. However, the first equation confuses me. It goes as follows: The pycnometer, placed on a balance, will exert a force: F = g(m_b - \frac{ \rho_a m_b}{ \rho_b}) The...
9. PHP HTML and PHP issue: display HTML form variables using PHP echo

Heeeeeeellllllllllllllooooooooooooo, I have a question about HTML and PHP: Firstly, I am using Apache2 and PHP5 (I think) and running it as a localhost. I created a simple HTML form that sends the variables via post to a PHP file; there are two variables with the names "nickname" and...
10. C: malloc() doesn't just allocate memory

Hello, Another (probably obvious) question: malloc() assigns memory space in bytes; e.g. malloc(100) assigns 100 bytes of space and returns a pointer. However, in creating a linked list, I can allocate space a assign it to a pointer and the structure already exists? For example...
11. C programming: pointer assignment only in main()?

Hello, I was assigning a pointer to an array and I noticed it will only this to takeplace within the main function: #include <stdio.h> float array_1[10] = { 1,1,2,3,4,5,6,7,8,9 }; float * p_array_1; int main( void ) { p_array_1 = &array_1; printf("array address using ampersand is %p...
12. C programming: array declared before main() and initialised in main()

Hello! I am sure I am again missing something obvious: I tried to declare the array and assing value within main() as follows: #include <stdio.h> float array_1[10]; int main( void ) { array_1[10] = { 1,1,2,3,4,5,6,7,8,9 }; ...other stuff... return 0; } I can declare and...
13. Simple C programming problem, variable stuck at initialised value

Simple C programming problem, variable "stuck" at initialised value Hello! This is most likely an error in my code but I just can't see what it is! I am new to C programming and maybe I have just been staring at it for so long that I can't see the obvious error. I was playing around with a...
14. Recommending installing Cygwin for Octave-use

Hello! I am not particularly well-versed in computers but I am interesting in expanding my knowledge. Basically, I have some familiarity with Matlab (from Uni), and I am interested in similar 'higher-level' numerical programming languages. Matlab is too expensive for a poor-person like...
15. Neuroscience: poisson and gauss in neuron firing rate model

Hello! I was reading a journal article on modeling the interaction between different neural networks and I am confused about the follwoing method (cited below). It is describing the spike rate output of a neuron based on oscillating firing rates of excitatory (E) and inhibitory (I) inputs...
16. Effectiveness of the United Nations locked

Hello! Why was my post in 'Effectiveness of the United Nations' censored without an explanation? I posted credible sources and all of the points where necessary to support my argument. I thought the major flaw with the politics forum is that no-one sites any sources. People seem to openly...
17. Neuroscience: LFP at fixed point with different simulataneous frequencies

Hello! I have a neuroscience question about local field potenitals (LFPs). I was reading a jounral article where the LFP in a given location was recorded overtime, and then the LFP at ecah time point was divided in to different frequency groups: i.e. the LFP at a given point in space...
18. Feedback on a report

Hello! I reported a post because a link in the post concerned me - nothing to do with the content of the post per se. I haven't had a response and I was wondering if I could get some feedback as to whether anyone else has some concern about it, or whether it is fine. I can provide more...
19. Integral for (kind of) standard Cauchy distibution and an alternative solution.

Hello! I have a couple of questions on the following. Firstly, I was hoping someone could check my working and my reasoning. Secondly, I was wondering if someone knew an alternative way of solving this problem. I wanted to integrate this from x = -\infty to x = \infty: \lim_{a...
20. Comp. Neuro. introductory textbooks

Hello! I know some people on the forum are computational neuroscientists (or related fields), and I was wondering if anyone could recommend a good introductory book. One that goes step-by-step through how the equations come about and why they are the way they are. Rather than books that...
21. Limit of otherwise equal summations is uneuqal due to indeterminate difference ?

Limit of otherwise equal summations is uneuqal due to "indeterminate difference"? Hello! I was working through a section on summation in a maths textbook because of a recent question I asked on the forum, and I came across something which is confusing. I am not sure if it is necessary, but...
22. Simplifying a summation

Homework Statement Hello! I'm guessing this is precalculus. There is an intermediate step in a simplifying process and I got to: \sum_{x=1}^n xA^{-Bx} Where A is a constant and B is a constant. Homework Equations I was wondering how to write this without the summation sign...
23. Indefinite integration substitutions: 'any' permissible?

Hello! Permissible is probably the wrong word, but here's what I am having difficulty with: With substitutions in integration to make the integral easier to solve, there doesn't seem to be a restriction on the substitution one can use with indefinite integration. If one function, or part...
24. Resonance structures you don't see

Hello! I have silly question on resonance, it's so silly, I couldn't find an answer: Lets say there is a O=CR-CH=CH2 bonding in a molecule, R = some other group. You can get (I have put the charges in brackets and Superposition (I think thats what its called): (1-)O-C=C-C(1+) (ignoring...
25. DNA agarose gel: one than one chromosome, one band.

Hello! If I run an agarose gel of undigested DNA of an organism with more than one chromosome, and obtain one band (slightly smeared), what does this mean? The chromosomes aren't all the same length (some might be approximately half the size of others). Is it because they all become...
26. Sp and sp2 orbital hybridisation, constructive and destructive.

Hello! When an s and a p orbital are hybridised to give and sp orbital, two orbitals are produced. According to my chemistry book, there are two orbitals due to in-phase and out-of-phase combinations of the the s and p orbitals. When we progress to sp2 hybridisation, there are three orbitals...
27. Nitrate ion lewis stucture

Hello! I was drawing the lewis structure for NO3- and was wondering why O=N-O-O- isn't a 'valid' predicted structure (Double-bonded O to nitrogen, a single-bonded oxygen to nitrogen, a lone pair on nitrogen, and a single-bonded oxygen to oxygen with a negative charge on the terminal oxygen...
28. Opening journal articles in new window.

Hello! Somewhat trivial question: When I open a pdf of a journal, it opens in a new window on the web browser (Opera). When I go to open a second article; sometimes when clicking on download pdf, sometimes when pressing "Go" in SFX Ex Libris, it replaces the other pdf. Sometimes I can...
29. New MIT eCourse

Anyone intend to start using the new MIT course?: BBC News: http://www.bbc.co.uk/news/education-17012968 "An electronics course, beginning in March, will be the first prototype of an online project, known as MITx. The interactive course is designed to be fully automated, with successful...
30. Swansea University puts up toilet instruction posters

It's Friday night, I'm bored and too fed up with everything to do anything constructive. As such: "Swansea University puts up toilet instruction posters". http://www.bbc.co.uk/news/uk-wales-south-west-wales-16983788 The picture is epic.